JP2015089248A - Heat radiation structure of electric connection box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat radiation structure of an electric connection box which is capable of efficiently emitting heat of a heat source.SOLUTION: A heat radiation structure of an electric connection box 1 comprises: a wiring board 11 mounting a heating component 12 thereon; a case 21 which houses the wiring board 11 inside thereof and supports the board; and a heat radiation component 31 which radiates heat from the heating component 12. In the heat radiation component 31, one end is a heat radiation opening part 32 and the other end is a closed heat transfer surface 33, and consists of a metal cylindrical body with a bottom in which a step part 35 is formed adjacent to the heat transfer surface 33. The case 21 has a case opening part 22 which houses the heat radiation component 31 such that the heat radiation opening part 32 faces outside the case 21 and the heat transfer surface 33 is arranged inside; and a fixing part 24 which fixes the wiring board 11 and the heat radiation component 31 to the case 21 such that a part of the fixing part is laid between the step part 35 and the wiring board 11, and the heat transfer surface 33 contacts a position at which the heating component 12 of the wiring board 11 is arranged.

Description

  The present invention relates to a heat dissipation structure for an electrical junction box, and particularly relates to a heat dissipation structure for an electrical junction box that can efficiently release heat from a heat source.

  In a board on which an electronic component used for operation control in an electric vehicle, a hybrid vehicle, or the like is mounted, the control may be adversely affected by heat released from the electronic component. As a countermeasure against heat generation of the electronic component, for example, a configuration in which a heat dissipation component is provided in the vicinity of the electronic component that generates heat is used.

  Conventionally, as a heat dissipation structure for heat generating electronic components, heat generated from the heat generating electronic components is released to the outside through the heat generating pattern by providing heat dissipating components in the fixing part that fixes the printed circuit board on which the heat generating electronic components are mounted. The structure (for example, patent document 1) to perform is known. In the invention described in Patent Document 1, a heat radiating nut for heat generation is insert-molded in a fixed portion, and a printed circuit board is screwed with a bolt using this heat radiating nut.

JP-A-9-32467

  In the configuration described in Patent Document 1, since the heat radiating nut is used to fix the printed circuit board, it cannot be disposed directly below the heat generating component. As a result, the heat dissipation effect by the heat dissipation nut is reduced. In order to increase the heat dissipation effect with the configuration described in Patent Document 1, it is necessary to widen the heat transfer surface (contact surface) between the printed circuit board and the heat dissipation nut, but in that case, the shape of the heat dissipation nut becomes larger. There is a problem that the weight increases. Moreover, since the area exposed to the outside of the case of the heat radiating nut is small, it is necessary to provide a separate heat radiator or a connection structure with a portion that can radiate heat, such as a vehicle body, in order to increase the heat radiation efficiency. And since the thermal radiation nut described in patent document 1 is insert-molded, there exists a problem that manufacturing cost starts.

  The present invention has been made in view of the above points, and even when a heat dissipation structure for an electrical junction box is installed, an electrical junction box that can easily and efficiently emit heat from a heat source. An object is to provide a heat dissipation structure.

  In order to solve the above problems and achieve the object, a heat dissipation structure for an electrical junction box according to the present invention includes a wiring board on which a heat generating component is mounted, a case that houses and supports the wiring board, and the heat generating component. And a heat dissipating component that dissipates heat from the heat. The heat radiating component is formed of a metal bottomed cylindrical body having a heat radiating opening at one end and a heat transfer surface with the other end closed, and a step portion formed adjacent to the heat transfer surface. The case includes a case opening that accommodates the heat dissipation component such that the heat dissipation opening faces the outside of the case and the heat transfer surface side is disposed inside, and a part of the step and the wiring board And a fixing portion for fixing the wiring board and the heat dissipating component to the case so that the heat transfer surface is in contact with a position where the heat generating component of the wiring board is disposed.

  Moreover, you may be comprised so that a part of side surface of the said heat radiating component may be exposed inside the said case. Furthermore, the part exposed to the inside of the case of the heat radiating component may be configured to be farthest from the heat transfer surface. Furthermore, the side surface of the heat dissipation component may be configured to be covered with the case and blocked from the inside of the case.

  Furthermore, a gap may be formed between the side surface of the heat dissipation component and the case. And the said heat radiating component may have the bell shape which the area of the cross section cut | disconnected along the said heat-transfer surface and the said heat-radiation opening part gradually expands from the said heat-transfer surface side to the said heat-radiation opening part side.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where the heat dissipation structure of an electrical junction box is installed, it is possible to provide the thermal dissipation structure of the electrical junction box which can discharge | release the heat | fever of a heat source simply and efficiently. Become.

It is sectional drawing which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the other example of the 2nd Embodiment of this invention. It is a perspective view which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the other example of the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 4th Embodiment of this invention. It is a perspective view which shows the structure of the thermal radiation structure of the electrical junction box which concerns on the 4th Embodiment of this invention.

[First Embodiment]
A heat dissipation structure for an electrical junction box according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of an electrical junction box 1 according to an embodiment of the present invention, and FIG. 2 shows a case 21 and a heat dissipation component in the configuration of the electrical junction box 1 according to an embodiment of the present invention. FIG. 1 is a cross-sectional view taken along the line A-A ′ of FIG. 2 and viewed in the direction of the arrow. In FIG. 2, illustration of the wiring board 11 is omitted, and only the case 21 and the heat dissipation component 31 are shown. However, the cross-sectional view of FIG. 1 includes a cross-sectional view including the entire wiring board 11 and the case 21. FIG. 3 is an exploded perspective view showing configurations of the wiring board 11, the case 21, and the heat dissipation component 31 used in the electrical junction box 1.

  As shown in FIGS. 1 and 3, a heat generating component 12 and other electronic components / wirings are mounted on a wiring board 11 provided in the electrical connection box 1. A heat conductive sheet 13 is attached to the back surface of the wiring board 11 where the heat generating component 12 is mounted. The heat conductive sheet 13 is provided to efficiently transmit the heat released from the heat generating component 12 to the heat radiating component 31 and promote the discharge of heat from the heat generating component 12. The wiring board 11 is formed with a fixing portion 14 for fixing the wiring board 11 to the case 21. A through hole corresponding to the diameter of the screw 41 is formed in the fixing portion 14 so that the wiring board 11 can be screwed to the case 21.

  As shown in FIGS. 1 to 3, the case 21 of the electrical junction box 1 is configured to accommodate and support the wiring board 11 in order to protect the wiring board 11. Further, if necessary, other parts and the like may be accommodated therein. The case 21 has a case opening 22 formed so that the heat dissipation component 31 can be accommodated. The case 21 according to the present embodiment is formed so that the upper portion covers the wiring board 11 and the lower portion has a case opening 22. However, the case opening 22 can be provided at an arbitrary position of the case 21 as necessary. The case opening 22 is formed with a heat dissipating component housing portion 23 that is continuous from the surface of the case 21 and that protrudes inward of the case 21. The heat radiation component housing portion 23 is formed so as to match the shape of the heat radiation component 31, but a part of the heat radiation component housing portion 23 may be cut out so that the inside of the case 21 and the outside of the case 21 penetrate. Good.

  As shown in FIGS. 1 to 3, the electrical junction box 1 is provided with a heat radiating component 31 for radiating heat from the heat generating component 12. The heat dissipating component 31 is a metal bottomed tubular body having one end as a heat dissipating opening 32 and the other end closing the heat transfer surface 33. The heat dissipation component 31 of the present embodiment is formed to have a bell shape in which the area of a cross section cut along the heat transfer surface 33 and the heat dissipation opening 32 extends from the heat transfer surface 33 side to the heat dissipation opening 32 side. ing. In other words, it can be said that the heat radiating component 31 has a hollow frustum shape in which the upper part is the heat transfer surface 33 and the lower part is the heat radiating opening 32. At a location adjacent to the heat transfer surface 33 of the heat radiating component 31, a step portion 35 is formed at a position closer to the heat dissipation opening 32 than the heat transfer surface 33 and has a step between the heat transfer surface 33. .

  The heat radiating component 31 is accommodated in the heat radiating component accommodating portion 23 of the case opening 22. At this time, the heat dissipation component 31 is accommodated such that the heat dissipation opening 32 of the heat dissipation component 31 faces the outside of the case 21 and the heat transfer surface 33 is disposed inside the case 21. As described above, since a part of the heat dissipation component accommodating portion 23 of the case 21 is cut out, a part of the side surface of the heat dissipation component 31 is exposed inside the case 21.

  As shown in FIGS. 1 and 3, the case 21, the wiring board 11, and the heat dissipation component 31 are fixed by screwing using fixing portions 14, 24, and 34. In the present embodiment, the fixing portion 24 of the case 21 is formed at an upper portion of the heat radiation component housing portion 23 provided in the case opening 22, that is, a location where the heat radiation component housing portion 23 protrudes inward. Yes. Further, the fixing portion 34 of the heat dissipation component 31 is formed in the step portion 35 of the heat dissipation component 31. The fixing portion 24 of the case 21 is provided so as to be interposed between the step portion 35 of the heat dissipation component 31 and the wiring board 11. The fixing part 24 and the fixing part 34 have a screw hole in which an internal thread is provided on the inner wall, and can be fixed in a state where the wiring board 11 is placed by the screw 41. The case 21, the wiring board 11, and the heat radiating component 31 are such that the heat transfer surface 33 of the heat radiating component 31 contacts the back surface of the wiring substrate 11 where the heat conductive sheet 13 is affixed, that is, the position where the heat generating component 12 is disposed. Fixed to.

Next, the effect of the heat dissipation structure of the electrical junction box 1 configured as described above will be described.
The heat released from the heat generating component 12 mounted on the wiring board 11 is transmitted to the heat radiating component 31 through the heat conductive sheet 13 on the back surface of the wiring board 11. The heat dissipating part 31 and the heat dissipating part accommodating part 23 of the case 21 have a structure protruding into the case 21, and the heat transfer surface 33 of the heat dissipating part 31 is connected to the outside air outside the case 21 through the heat dissipating opening 32. In contact. Therefore, the heat transferred to the heat transfer surface 33 of the heat dissipation component 31 is discharged from the heat dissipation opening 32 to the outside of the case 21. Further, the heat inside the case 21 is also discharged to the outside of the case 21 through the location where the heat dissipation component 31 is exposed inside the case 21. As a result, excessive heat is not trapped inside the heat generating component 12 and the case 21 of the wiring board 11, and the heat generating component 12 can be prevented from malfunctioning due to overheating. According to the heat dissipation structure of the electrical junction box 1 according to the present embodiment, sufficient heat dissipation performance can be obtained without providing a heatsink separately from the heat dissipation component 31 or connecting to a vehicle body or the like.

  Further, the fixing portions 14 and 34 of the wiring board 11 and the heat radiating component 31 are formed at locations different from the contact portion between the heat generating component 12 and the heat radiating component 31 (the heat transfer surface 33 of the heat radiating component 31). The heat transfer surface 33 of the heat dissipating component 31 can be freely changed in location, and the heat transfer surface 33 of the heat dissipating component 31 can be disposed in the vicinity of the heat generating component 12. Furthermore, since the case 21, the heat radiating component 31, and the like are made from a plate material by press molding or the like, the degree of freedom in shape is large, and the area of the heat transfer surface 33 can be expanded. Since the heat dissipating component 31 and the case 21 are formed as separate components, the heat dissipating component 31 can be retrofitted to the case 21. Further, there is no need for insert molding, and the manufacturing process can be simplified.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. The overall configuration of the heat dissipation structure for the electrical junction box of the present embodiment is the same as that of the first embodiment, and a detailed description thereof is omitted. Moreover, the same code | symbol is attached | subjected to the location which has the structure similar to 1st Embodiment, and the overlapping description is abbreviate | omitted. The heat dissipation structure of the electrical junction box of the present embodiment is different from the first embodiment in the shape of the heat dissipation component accommodating portion 23.

  4 and 5 are a cross-sectional view and a perspective view of the heat dissipation structure of the electrical junction box of the present embodiment, corresponding to the heat dissipation structure of the electrical junction box of the first embodiment shown in FIGS. 1 and 2. The part to do is illustrated. 4 is a cross-sectional view showing the wiring board 11, the case 21, and the heat dissipation component 31, and FIG. 5 is a perspective view showing only the case 21. As shown in FIG. In the heat dissipation structure for the electrical junction box according to the present embodiment, the heat dissipation component 31 is disposed in the heat dissipation component accommodating portion 23 of the case opening 22. The heat dissipating component 31 is fixed so that the heat dissipating opening 32 faces the outside of the case 21, the heat transfer surface 33 side faces the inside, and the heat transfer surface 33 contacts the position where the heat generating component 12 of the wiring board 11 is disposed. This is the same as in the first embodiment.

  As shown in FIGS. 4 and 5, the heat dissipation structure of the electrical junction box of the present embodiment is different from that of the first embodiment in that a part of the side surface of the heat dissipation component 31 is exposed inside the case 21. It is the same. However, it differs from the first embodiment in that the portion of the heat radiation component 31 exposed inside the case 21 is limited to the portion farthest from the heat transfer surface 33. Of the heat dissipating part accommodating part 23, a part cut out so as to penetrate the inside of the case 21 and the outside of the case 21 is limited to a part below the fixing part 24. For this reason, the portion exposed to the inside of the case 21 other than the heat transfer surface 33 of the heat radiating component 31 is only the portion farthest from the heat transfer surface 33 located at the tip of the step portion 35.

  Even in the heat dissipation structure of the electrical junction box configured as described above, the heat released from the heat generating component 12 mounted on the wiring substrate 11 is transferred to the heat dissipation component 31 through the heat conductive sheet 13 on the back surface of the wiring substrate 11. Communicated. The heat released from the heat generating component 12 is discharged from the heat transfer surface 33 of the heat radiating component 31 to the outside of the case 21 through the heat radiating opening 32. As a result, excessive heat is not trapped inside the heat generating component 12 and the case 21 of the wiring board 11, and the heat generating component 12 can be prevented from malfunctioning due to overheating.

  Here, when the portion exposed to the inside of the case 21 of the heat radiating component 31 is in the vicinity of the heat transfer surface 33, the heat transmitted through the heat transfer surface 33 rather than releasing the heat inside the case 21 is the case. There is a possibility that the action of moving to the inside of the 21 becomes larger, and the temperature inside the case 21 rises. However, by limiting the position where the heat dissipating component 31 and the air inside the case 21 are in contact with the position away from the heat generating component 12, the heat inside the case 21 is not overheated. Can be released to the outside.

[Another example of the second embodiment]
Next, another example of the second embodiment of the present invention will be described with reference to FIGS. The overall configuration of the heat dissipation structure of the electrical junction box of this example is the same as that of the second embodiment, and detailed description thereof is omitted.

  6 and 7 are a cross-sectional view and a perspective view of the heat dissipation structure of the electrical junction box of the present embodiment, and correspond to the heat dissipation structure of the electrical junction box of the second embodiment shown in FIGS. 4 and 5. The part to do is illustrated. In the second embodiment, the heat dissipation structure of the electrical junction box of the present example is also limited to a portion where the portion exposed to the inside of the case 21 of the heat dissipation component 31 is farthest from the heat transfer surface 33. It is the same as the form.

  As shown in FIGS. 6 and 7, a portion of the heat dissipation component housing 23 that is cut out so as to penetrate the inside of the case 21 and the outside of the case 21 is cut out as it becomes closer to the case opening 22. It is configured to spread. Further, the portion exposed to the inside of the case 21 located at the tip of the step portion 35 of the heat radiation component 31 is provided with a step so as to widen the heat radiation opening 32 and is configured to match the heat radiation component accommodation portion 23. Yes.

  Even with the heat dissipation structure of the electrical junction box configured as described above, the same effects as those of the second embodiment can be obtained. Further, the area where the heat radiating component 31 and the air inside the case 21 are in contact with each other can be made larger than in the second embodiment, and the heat inside the case 21 can be released efficiently.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. The overall configuration of the heat dissipation structure for the electrical junction box of the present embodiment is the same as that of the first embodiment, and a detailed description thereof is omitted. Moreover, the same code | symbol is attached | subjected to the location which has the structure similar to 1st Embodiment, and the overlapping description is abbreviate | omitted. The heat dissipation structure of the electrical junction box of the present embodiment is different from the first embodiment in the shape of the heat dissipation component accommodating portion 23.

  8 and 9 are a cross-sectional view and a perspective view of the heat dissipation structure of the electrical junction box of the present embodiment, corresponding to the heat dissipation structure of the electrical junction box of the first embodiment shown in FIGS. 1 and 2. The part to do is illustrated. FIG. 8 is a cross-sectional view showing the wiring board 11, the case 21, and the heat dissipation component 31, and FIG. 9 is a perspective view showing only the case 21. In the heat dissipation structure for the electrical junction box according to the present embodiment, the heat dissipation component 31 is disposed in the heat dissipation component accommodating portion 23 of the case opening 22. The heat dissipating component 31 is fixed so that the heat dissipating opening 32 faces the outside of the case 21, the heat transfer surface 33 side faces the inside, and the heat transfer surface 33 contacts the position where the heat generating component 12 of the wiring board 11 is disposed. This is the same as in the first embodiment.

  As shown in FIGS. 8 and 9, in the heat dissipation structure of the electrical junction box of the present embodiment, the side surface of the heat dissipation component 31 is covered with the heat dissipation component housing portion 23 of the case 21, and the heat dissipation component 31 is the case 21. The second embodiment is different from the first embodiment in that it is cut off from the inside. The part cut out so that the inside of the case 21 and the outside of the case 21 pass through is limited to the part immediately below the part where the heat conductive sheet 13 of the wiring board 11 is affixed. Therefore, when the heat radiating component 31 is fixed to the case 21, the side surfaces of the heat radiating component 31 are all covered with the case 21, and the side surfaces of the heat radiating component 31 and the inside of the case 21 are isolated.

  Even in the heat dissipation structure of the electrical junction box configured as described above, the heat released from the heat generating component 12 mounted on the wiring substrate 11 is transferred to the heat dissipation component 31 through the heat conductive sheet 13 on the back surface of the wiring substrate 11. Communicated. The heat released from the heat generating component 12 is discharged from the heat transfer surface 33 of the heat radiating component 31 to the outside of the case 21 through the heat radiating opening 32. As a result, excessive heat is not trapped inside the heat generating component 12 and the case 21 of the wiring board 11, and the heat generating component 12 can be prevented from malfunctioning due to overheating.

  Here, when there is a lot of heat that moves from the heat dissipation component 31 to the inside of the case 21 through the opening of the heat dissipation component accommodating portion 23, the temperature inside the case 21 rises regardless of the arrangement of the opening of the heat dissipation component accommodating portion 23. There is a risk that. Therefore, as shown in the present embodiment, by covering all the side surfaces of the heat radiating component 31 and isolating the heat radiating component 31 and the air inside the case 21, the case 21 is prevented from overheating. The temperature rise inside can be suppressed.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. The overall configuration of the heat dissipation structure for the electrical junction box of the present embodiment is the same as that of the first embodiment, and a detailed description thereof is omitted. Moreover, the same code | symbol is attached | subjected to the location which has the structure similar to 1st Embodiment, and the overlapping description is abbreviate | omitted. The heat dissipation structure of the electrical junction box of the present embodiment is different from the first embodiment in the shapes of the heat dissipation component housing portion 23 and the heat dissipation component 31.

  FIG. 10 is a cross-sectional view of the heat dissipation structure of the electrical junction box of the present embodiment, and illustrates portions corresponding to the heat dissipation structure of the electrical junction box of the first embodiment shown in FIG. FIG. 10 is a cross-sectional view showing the wiring board 11, the case 21, and the heat dissipation component 31. FIG. 11 is a perspective view of the heat dissipation structure of the electrical junction box of the present embodiment. FIG. 11 is a diagram illustrating a state in which the case opening 22 and the heat radiation opening 32 of the heat radiation component 31 are viewed from the outside of the case 21.

  In the heat dissipation structure for the electrical junction box according to the present embodiment, the heat dissipation component 31 is disposed in the heat dissipation component accommodating portion 23 of the case opening 22. The heat dissipating component 31 is fixed so that the heat dissipating opening 32 faces the outside of the case 21, the heat transfer surface 33 side faces the inside, and the heat transfer surface 33 contacts the position where the heat generating component 12 of the wiring board 11 is disposed. This is the same as in the first embodiment.

  As shown in FIGS. 10 and 11, in the heat dissipation structure of the electrical junction box of the present embodiment, the side surface of the heat dissipation component 31 is covered with the heat dissipation component housing portion 23 of the case 21, and the heat dissipation component 31 is the case 21. This is similar to the third embodiment in that it is cut off from the inside. The heat dissipation structure of the electrical junction box of the present embodiment is different from that of the third embodiment in that a gap S is formed between the side surface of the heat dissipation component 31 and the heat dissipation component accommodating portion 23 of the case 21. In the example shown in FIG.10 and FIG.11, it is comprised so that a part of side surface of the thermal radiation component 31 may dent toward the inner side of the cylindrical thermal radiation component 31 which is hollow. However, the heat dissipation structure of the electrical junction box of the present embodiment only needs to form a gap S between the heat dissipation component 31 and the heat dissipation component accommodating portion 23 of the case 21. By changing the shape, a gap may be formed between the heat dissipation component 31 and the heat dissipation component accommodating portion 23 of the case 21.

  Even in the heat dissipation structure of the electrical junction box configured as described above, the heat released from the heat generating component 12 mounted on the wiring substrate 11 is transferred to the heat dissipation component 31 through the heat conductive sheet 13 on the back surface of the wiring substrate 11. Communicated. The heat released from the heat generating component 12 is discharged from the heat transfer surface 33 of the heat radiating component 31 to the outside of the case 21 through the heat radiating opening 32. As a result, excessive heat is not trapped inside the heat generating component 12 and the case 21 of the wiring board 11, and the heat generating component 12 can be prevented from malfunctioning due to overheating.

  And by providing the clearance gap S between the heat radiating component 31 and the heat radiating component accommodating part 23 of the case 21, since the heat transmitted to the heat radiating component 31 is more exposed to the outside air, the heat radiating performance can be improved.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, the heat dissipation structure for the electrical junction box described in the embodiment can be implemented in combination. Further, the heat dissipation structure of the electrical junction box described in the embodiment has been described on the assumption that the heat transfer surface 33 of the heat dissipation component 31 is in contact with the back surface of the wiring board 11 on which the heat generating component 12 is mounted. It is not something that can be done. That is, the front and back of the wiring board 11 shown in the embodiment can be reversed, and the heat generating component 12 can be in direct contact with the heat transfer surface 33.

  Moreover, the heat conductive sheet 13 does not necessarily need to be provided, and a configuration in which this is omitted may be employed. However, the heat conductive sheet 13 is provided at a location where the heat dissipation component 31 and the wiring board 11 are in contact with each other, and has a function of reducing the force (contact pressure) applied between the heat dissipation component 31 and the wiring board 11. You can also. When the heat conductive sheet 13 is not provided, the contact pressure between the heat dissipation component 31 and the wiring board 11 increases, and the wiring board 11 may be damaged, but the contact pressure between the heat dissipation component 31 and the wiring board 11 is reduced. By providing the heat conductive sheet 13 having a function to perform such a problem, it is possible to prevent such a problem.

  DESCRIPTION OF SYMBOLS 1 ... Electrical junction box, 11 ... Wiring board, 12 ... Heat-generating component, 13 ... Thermally conductive sheet, 14 ... Fixed part, 21 ... Case, 22 ... Case opening , 23... Heat radiating component accommodating portion, 24... Fixing portion, 31... Heat radiating component, 32 .. heat radiating opening, 33 .. heat transfer surface, 34. ..Steps, 41 ... screws.

Claims (6)

A wiring board on which a heat generating component is mounted; a case that houses and supports the wiring board; and a heat dissipating component that dissipates heat from the heat generating component.
The heat dissipating component comprises a bottomed cylindrical body made of metal in which one end is a heat dissipating opening and the other end is closed as a heat transfer surface, and a step is formed adjacent to the heat transfer surface.
The case is
A case opening that accommodates the heat dissipation component such that the heat dissipation opening faces the outside of the case and the heat transfer surface side is disposed inside;
The wiring board and the heat dissipating component are placed in the case so that a part is interposed between the stepped portion and the wiring board, and the heat transfer surface is in contact with the position where the heat generating component of the wiring board is disposed. And a heat dissipating structure for the electrical junction box.   The heat dissipation structure for an electrical junction box according to claim 1, wherein a part of the side surface of the heat dissipation component is exposed inside the case.   3. The heat dissipation structure for an electrical junction box according to claim 2, wherein a portion of the heat dissipation component exposed inside the case is farthest from the heat transfer surface.   2. The heat dissipation structure for an electrical junction box according to claim 1, wherein a side surface of the heat dissipation component is covered with the case and blocked from the inside of the case.   The heat dissipation structure for an electrical junction box according to claim 1, wherein a gap is formed between a side surface of the heat dissipation component and the case.   The heat dissipation component has a bell shape in which an area of a cross section cut along the heat transfer surface and the opening gradually increases from the heat transfer surface to the heat dissipation opening. The heat dissipation structure of the electrical junction box described in the section.

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